JAVA-2616: Wait for at least one connected server to be available when determining whether to apply an implicit session

Author: jyemin

driver/src/main/com/mongodb/Mongo.java

@@ -43,6 +43,7 @@
 import com.mongodb.operation.ReadOperation;
 import com.mongodb.operation.WriteOperation;
 import com.mongodb.selector.LatencyMinimizingServerSelector;
+import com.mongodb.selector.ServerSelector;
 import org.bson.BsonBoolean;
 import org.bson.BsonDocument;
 import org.bson.BsonTimestamp;
@@ -853,13 +854,31 @@ ClientSession getClientSession(final ClientSession clientSessionFromOperation) {
     }
 
     ClientSession createClientSession(final ClientSessionOptions options) {
-        if (cluster.getDescription().getLogicalSessionTimeoutMinutes() != null && credentialsList.size() < 2) {
+        if (credentialsList.size() > 1) {
+            return null;
+        }
+        if (getConnectedClusterDescription().getLogicalSessionTimeoutMinutes() != null) {
             return new ClientSessionImpl(this, options);
         } else {
             return null;
         }
     }
 
+    @SuppressWarnings("deprecation")
+    private ClusterDescription getConnectedClusterDescription() {
+        ClusterDescription clusterDescription = cluster.getDescription();
+        if (clusterDescription.getAny().isEmpty()) {
+            cluster.selectServer(new ServerSelector() {
+                @Override
+                public List<ServerDescription> select(final ClusterDescription clusterDescription) {
+                    return clusterDescription.getAny();
+                }
+            });
+            clusterDescription = cluster.getDescription();
+        }
+        return clusterDescription;
+    }
+
     static class ClientSessionImpl implements ClientSession {
         private static final String CLUSTER_TIME_KEY = "clusterTime";
 

driver/src/test/functional/com/mongodb/MongoClientSessionSpecification.groovy

@@ -230,15 +230,14 @@ class MongoClientSessionSpecification extends FunctionalSpecification {
         def optionsBuilder = MongoClientOptions.builder()
                 .addCommandListener(commandListener)
         def client = new MongoClient(Fixture.getMongoClientURI(optionsBuilder))
-        // TODO: Remove this once SPEC-944 is resolved
-        client.getDatabase('admin').runCommand(new BsonDocument('ping', new BsonInt32(1)))
 
         when:
         client.getDatabase('admin').runCommand(new BsonDocument('ping', new BsonInt32(1)))
 
         then:
-        def pingCommandStartedEvent = commandListener.events.get(2)
-        (pingCommandStartedEvent as CommandStartedEvent).command.containsKey('lsid')
+        commandListener.events.size() == 2
+        def pingCommandStartedEvent = commandListener.events.get(0) as CommandStartedEvent
+        pingCommandStartedEvent.command.containsKey('lsid')
 
         cleanup:
         client?.close()